It's perfectly safe to run Cat5 parallel to power lines (or any other EMI source). The twisting of the wire pairs cancels out almost all interference.
A tutorial on how to use RJ-45 UTP cabling for video transmission and camera control as you migrate toward IP-based wiring An illustration shows a suggested format for connecting analog video ...
Coaxial cable: Coax is good for short wire runs in low-noise environments. Its thick copper construction yields low signal losses. As an unbalanced transmission-line, its interference immunity is poor ...